Mathematical Economical Problems

I am currently doing A2 but would like to look at problems that would require me to use my A2 Maths knowledge in S1, S2, C1-4 to solve/complete.

Are there any basic UG questions you would advise me to look at? Is there a website with such questions?

Best thing I have seen is finding productive efficiency with calculus. Not many questions out there.

The sort of maths used at UG level is mainly statistics (called econometrics, which mainly concerns itself with regression analysis) and optimisation problems (which is differentiation with a constraint). Google optimisation problems if your interested. However, with just A level knowledge, though im sure you have the mathematical ability, you may not have the economic theoretical understanding